package de.slothsoft.wasbinich.android;

import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import de.slothsoft.wasbinich.android.util.ActivityUtil;
import de.slothsoft.wasbinich.core.FullPicture;
import de.slothsoft.wasbinich.core.database.Database;
import de.slothsoft.wasbinich.core.util.ExceptionUtil;

/**
 * A list fragment representing a list of Pictures. This fragment also supports
 * tablet devices by allowing list items to be given an 'activated' state upon
 * selection. This helps indicate which item is currently being viewed in a
 * {@link PictureDetailFragment}.
 * <p>
 * Activities containing this fragment MUST implement the {@link Callbacks}
 * interface.
 */
public class PictureListFragment extends ListFragment {

    /**
     * The serialization (saved instance state) Bundle key representing the
     * activated item position. Only used on tablets.
     */
    private static final String STATE_ACTIVATED_POSITION = "activated_position";//$NON-NLS-1$

    /**
     * The fragment's current callback object, which is notified of list item
     * clicks.
     */
    private Callbacks mCallbacks = sDummyCallbacks;

    /**
     * The current activated item position. Only used on tablets.
     */
    private int mActivatedPosition = ListView.INVALID_POSITION;

    /**
     * A callback interface that all activities containing this fragment must
     * implement. This mechanism allows activities to be notified of item
     * selections.
     */
    public interface Callbacks {
	/**
	 * Callback for when an item has been selected.
	 */
	public void onItemSelected(Long id);
    }

    /**
     * A dummy implementation of the {@link Callbacks} interface that does
     * nothing. Used only when this fragment is not attached to an activity.
     */
    private static Callbacks sDummyCallbacks = new Callbacks() {
	@Override
	public void onItemSelected(Long id) {
	}
    };

    protected List<FullPicture> shownPictures;

    @Override
    public void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);

	new Thread(new Runnable() {
	    @Override
	    public void run() {
		try {
		    PictureListFragment.this.shownPictures = Database.getInstance().getManagerBean().getPictures();
		    getActivity().runOnUiThread(new Runnable() {
			@Override
			public void run() {
			    setListAdapter(new ArrayAdapter<FullPicture>(getActivity(),
				    android.R.layout.simple_list_item_1, PictureListFragment.this.shownPictures));
			}
		    });
		} catch (Exception exception) {
		    ActivityUtil.handleException(getActivity(), exception);
		    if (ExceptionUtil.isCancelledByUserException(exception)) {
			getActivity().finish();
		    }
		}
	    }
	}).start();
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
	super.onViewCreated(view, savedInstanceState);

	// Restore the previously serialized activated item position.
	if (savedInstanceState != null && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
	    setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
	}
    }

    @Override
    public void onAttach(Activity activity) {
	super.onAttach(activity);

	// Activities containing this fragment must implement its callbacks.
	if (!(activity instanceof Callbacks))
	    throw new IllegalStateException("Activity must implement fragment's callbacks.");//$NON-NLS-1$

	this.mCallbacks = (Callbacks) activity;
    }

    @Override
    public void onDetach() {
	super.onDetach();

	// Reset the active callbacks interface to the dummy implementation.
	this.mCallbacks = sDummyCallbacks;
    }

    @Override
    public void onListItemClick(ListView listView, View view, int position, long id) {
	super.onListItemClick(listView, view, position, id);

	// Notify the active callbacks interface (the activity, if the
	// fragment is attached to one) that an item has been selected.
	this.mCallbacks.onItemSelected(this.shownPictures.get(position).id);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
	super.onSaveInstanceState(outState);
	if (this.mActivatedPosition != ListView.INVALID_POSITION) {
	    // Serialize and persist the activated item position.
	    outState.putInt(STATE_ACTIVATED_POSITION, this.mActivatedPosition);
	}
    }

    /**
     * Turns on activate-on-click mode. When this mode is on, list items will be
     * given the 'activated' state when touched.
     */
    public void setActivateOnItemClick(boolean activateOnItemClick) {
	// When setting CHOICE_MODE_SINGLE, ListView will automatically
	// give items the 'activated' state when touched.
	getListView().setChoiceMode(activateOnItemClick ? ListView.CHOICE_MODE_SINGLE : ListView.CHOICE_MODE_NONE);
    }

    private void setActivatedPosition(int position) {
	if (position == ListView.INVALID_POSITION) {
	    getListView().setItemChecked(this.mActivatedPosition, false);
	} else {
	    getListView().setItemChecked(position, true);
	}

	this.mActivatedPosition = position;
    }

}
